AmpliSafe® - Durability in corrosive environments

___________________________________________________________________________________________ Normeka AS Østkroken 242 Phone WEB VAT number NO-1950 Rømskog +47 69 85 90 90 NO 950 819 510 MVA Rømskog 2019.08.15 AmpliSafe® – durability in corrosive environments Aluminium - General properties A few of the most widely known properties of aluminium is the low weight of the material and its unique ability to withstand long-term service in most kinds of climates or environments in its natural untreated state. The secret behind the ability to withstand corrosion or other degrading in a wide array of environments is that aluminium spontaneously reacts with oxygen and creates a thin oxide layer which protects the underlying material from further corrosion. If this thin oxide layer is scratched or otherwise damaged, it instantly will start to regenerate as long as oxygen is present. A few examples of untreated aluminium proving its excellent ability to withstand the elements in long-term outdoor use, are the pyramid-shaped top of the Washington Monument in Washington, D.C, and the statue of Eros in Piccadilly Circus, London. Both examples still stand, virtually unaffected after some 130 years. Perhaps the statue of Eros is the most impressive considering the highly polluted air which London has suffered during large parts of the 20 th century. Aluminium – Seawater and coastal areas Even though aluminium will withstand most natural outdoor environments unaffected there are a few exceptions, of which seawater or immediate seaside areas can be one. When an application will be either submerged in seawater or in immediate proximity of seawater, caution must be taken to choose an aluminium alloy which will withstand the more aggressive environment that seawater presents. Aluminium alloys in the EN-AW 5000 and EN-AW-6000 series are suitable for use in this kind of environment. Aluminium – Galvanic corrosion Any connection between dissimilar metals may result in galvanic corrosion if there is a direct metal to metal connection between the dissimilar metals and an electrolyte, e.g. seawater, which will close the electrical circuit needed for galvanic corrosion to occur. The less noble of the two metals will constitute the anode and the more noble the cathode If all conditions are fulfilled for a galvanic cell to form, the anode will corrode at a faster pace than the material would have done on its own. The